First you need to fix the problem about your ever changing route to your hoem computer....either get a static IP address...boo more $$$ or go and sign up for
Dynamic DNS , which would allow you to type in say...bobbigbox.dyndns.org and you would connect to your current ip address at home...of course you need to download there client software that keeps your ip/dns info updated in real time...or whatever settings you set...
service to run remote connections.
i want go into alot of detail about remote connectivity but, it should be easy since, your running xp.
RDC (remote desktop connection) i would recommend creating a new account just for the purpose of remote connectivity.
Now the web cam, not sure atm. You sould be able to veiw the cam through your home desktop /w RDC. not sure though....
let me know